Reconstruction model of the ancient Izumo-taisha honden, based on remains of old pillars found on the site.

Reconstruction of Izumo Taisha's honden somewhat later, during the Kamakura period

Izumo Taisha's honden over time has gone through profound changes that have greatly decreased its size and changed its structure.[8] In its present form, it is a gabled building 2x2 ken[9] in size, with an entrance on the gabled end (a characteristic called tsumairi-zukuri (妻入造). Like Ise Grand Shrine's, it has purely ornamental poles called chigi (vertical) and katsuogi (horizontal) on a cypress bark-covered roof, plus archaic features like gable-end pillars and a single central pillar (shin no mihashira (心の御柱)).[8] This pillar has a diameter of 10.9 cm, has no obvious structural role and is believed to have had a purely religious significance.[10] The external stairway is covered by an independent bark-covered roof (see illustration in the gallery).

Izumo Taisha's honden

The honden's interior is a square divided into four identical sections, each covered by 15 tatami (straw mats). The floor plan has therefore the shape of the Chinese character for rice field (田), an element which suggests a possible connection with harvest propitiation rites.[10]

Because its floor is raised above the ground, the honden is believed to have its origin in raised-floor granaries like those found in Toro, Shizuoka prefecture.[10]

The oldest extant example of taisha-zukuri is the honden at Kamosu Shrine in Matsue, Shimane prefecture, built in 1582 and now declared a National Treasure.[8] Smaller than Izumo Taisha's, it nonetheless has thick supporting pillars. It is deeper, has a higher floor, and differs significantly from Izumo Taisha's. It probably represents an older style of construction.[8]

^A ken is the distance between one supporting pillar and another, a quantity which can vary from shrine to shrine and even within the same building. In this case, a ken is 6.32 m, well above its standard value of just below 2 m.